The use of steamed catalysts in isomerization processes is described in the art and literature. For example, U.S. Pat. No. 5,166,112 claims and describes a steamed catalyst containing zeolite Beta and a Group VIII metal, and U.S. Pat. No. 5,082,988 claims the use of a similar catalyst in isomerizing a feedstream containing predominantly C5 to C7 hydrocarbons.
U.S. Pat. No. 4,418,235 discloses the use of zeolites with a pore dimension greater than about 5 Angstroms, preferably 10-membered rings, with a silica to alumina ratio of at least 12 and a constraint index of about 1 to about 12. These zeolites undergo a treatment with steam or water prior to use and are used in an acid catalyzed conversion process.
U.S. Pat. No. 4,374,296 discloses the use of zeolites with a pore dimension greater than about 5 Angstroms, preferably 10-membered rings, with a silica to alumina ratio of greater than 12 and a constraint index of about 1 to about 12. The catalysts undergo a controlled treatment to enhance the acidity, expressed as alpha, to about 300. These catalysts are used in the hydroisomerization of a C4 to C8 paraffin.
All of the above referenced patents are hereby incorporated by reference.
However, there still exists a need in the art for an improved process for isomerizing a C10+ hydrocarbon feedstream.